Imagine being in the Iranian military now. You have US forces basically able to hit you from the gulf, Indian Ocean, Iraq, and Afghanistan. And the Israelis likely to participate, probably via Iraqi airspace.
You can count the US forces out now that His Majesty is in charge, but I see your point. What we DO have as a check against Iran is the US-trained and equipped Iraqi military. In 2009, they’re scheduled to receive M1 tanks, artillery, and Little Bird attack helicopters. They already have placed orders for F-16s.
Plus Iran can’t be too happy that there’s a free press and open market economy next door to them. The Syrians can’t be too happy either.
And they have sufficient air superiority, firepower, training and logistical support to make God himself jealous.